In digital circuits, the current drawn from the power supply is a fundamental problem, with applications in several areas such as substrate noise analysis (SNA) of mixed-signal systems, power dissipation in digital circuits, and interconnect reliability (for instance, due to electromigration). Of interest are both instantaneous current in response to the transitions at the circuit inputs in a given clock cycle and the maximum current over all possible input transitions.
Designers typically use a circuit simulator, such as SPICE, for current, noise and power analysis. The circuit model typically consists of a composition of accurate device and interconnect models. However, it is not feasible to simulate such a circuit model on a circuit with even 100,000 gates. With chip complexity up to millions of gates, it is important to derive high-level models and methodologies to enable an efficient yet accurate chip-level current analysis. The results of research into deriving such reduced models (RMs) have been unsatisfactory. The resulting RMs are typically inaccurate or unsuitable for chip-level analysis.